Back in 2005, Robyn Sue Goldman had an idea, but she wasn’t quite sure how to execute it. “I wanted to re-invent old-fashioned ice cream without all the preservatives and stabilizers you get in regular ice cream,” Goldman thought.

She then teamed up with some engineers to develop a method for just that —the churned-out-back taste and texture of just-made ice cream using only the freshest ingredients. Three years later, Smitten Ice Cream and the invention that enabled it was born. The machine, affectionately named “Kelvin,” is a triple-patented liquid nitrogen-freezing magician that turns a milk-cream-flavor mixture from liquid to ice cream in one minute. Seriously. Check out Kelvin in action in this video from NBC's The Feast.

Goldman began her ice cream career in a food cart back in 2008. “I put Kelvin on the back of a Radio Flyer wagon and a battery pack I made that would last three hours,” said Goldman.

After a few years of carting around Kelvin, Goldman opened her first store last month in Hayes Valley. Housed in a recycled shipping container, the store is the first installation of the temporary foodie compound The Proxy Project, which is slated to include a Ritual Coffee and a biergarten from Suppenkuche. The Smitten shop is packed with four Kelvins, and all the ingredients are made in-house (or, in-shipping container).

When the liquid nitrogen freezes the cream mixture, it creates smaller ice crystals than what is in a typical, store-bought ice cream, which in turn creates an extremely light yet creamy texture. With flavors ranging from salted-caramel to rhubarb crisp (with a rosemary streusel), a heaping scoop of this fluffy, made-to-order goodness sits atop one of Smitten’s hand-rolled pizelle cones. It's the perfect treat to have while you sit in the park or walk around Hayes Valley during a sunny afternoon.